Based On Ultrasonic Resonant Cavity Of The Hydrogen Detection System Research And Design

In the present gas detection technology has been widely used, but the performance of the gas detection system is always unsatisfied. There are many problems such as poor stability, corrosion resistance, and low sensitivity and so on.According to the current domestic and international status of research on hydrogen test, this dissertation analyzes the acoustic characteristics difference between hydrogen and other gases. In the same conditions, the air velocity is about 1 / 4 of hydrogen, and acoustic impedance is about 4 times of the hydrogen. The hydrogen sensor based on ultrasonic resonator uses the significant characteristics differences between the hydrogen and air, selects quartz as the piezoelectric material, uses two inverse piezoelectric effects to detect the resonant frequency of different concentrations of hydrogen. Different from the semiconductor-type sensors this design uses the acoustic characteristics of the gas to detect rather than the gas sensors. The performance of sensitivity and resistance to corrosion is greatly improved.The hydrogen detection system based on ultrasonic resonator in this design includes hydrogen detection module, signal processing module, the wireless transceiver module and the display module. Hydrogen sensors convert the current hydrogen concentration n to the frequency output f (n). And after mixing, a lower frequency can be produced. This frequency can be directly sent to MCU count. And the count n can be changed into the hydrogen concentration code by mathematical calculation model. Then, the hydrogen concentration code is transferred by transceiver chip nRF401, and finally displayed on the LCD.Experimental results show that the hydrogen detection system has an effective communication distance of 50 meters. This design has the advantages of low power, small size and can be used in the environment people can not enter. It has great practicability and economical efficiency.